1. Field of the Invention
The present invention relates to a fixing device fixing a toner image onto a paper at a nip area formed between a fixing member and a pressing member, and also relates to image forming apparatuses comprising same.
2. Description of the Related Art
A fixing device of an image forming apparatus generally includes a fixing roller, or a fixing belt wound onto a fixing roller (fixing member), and a pressing roller (pressing member) that contacts the fixing member to form a nip area between the pressing roller and the fixing member, and a toner image on a paper that is conveyed in is thermally fixed onto the paper. With the fixing device, there are cases where a paper that has undergone the fixing process is discharged from the nip area while being stuck to the fixing member, and in these cases problems are caused such as paper jam.
To eliminate such problems, in a first technology for example, the fixing device is provided with a separation mechanism, which is configured so as to be capable of stripping from the fixing member the paper that has stuck to the fixing member after the fixing process. The separation mechanism is provided with a single separation plate (separation member) that extends in a longitudinal direction of the fixing roller in a state in which it is kept apart from the fixing roller by a predetermined gap, and a plurality of screw members that are arranged leaving a predetermined interval between each other in the longitudinal direction of the separation plate and that contact the separation plate. When a screw member is rotated, an amount of contact of the screw member against the separation plate changes, and the magnitude of the gap between the separation plate and the fixing roller changes. That is, in this separation mechanism, the gap between the separation plate and the fixing roller can be adjusted at multiple locations on the separation plate. And by setting this gap to a predetermined magnitude, the separation plate contacts the paper that has stuck to the fixing roller and is able to strip the paper from the fixing roller.
The separation plate of the first technology is configured from a single separation member, and therefore when adjustment is carried out of the gap between a single portion of the separation plate and the fixing roller by rotating any of the screw members, the magnitude of the gap between other portions of the separation plate and the fixing roller changes undesirably. And it is necessary to readjust the changed gap so that it achieves the predetermined magnitude. Unfortunately, in this way, with the separation mechanism of the first technology, time is required in adjusting the gap between the separation plate and the fixing roller.